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The keyboard is a bit glitchy, but these are the same glitch as those that were already present in Z80 Collapse OS. They still need fixing...
63 lines
2.2 KiB
Markdown
63 lines
2.2 KiB
Markdown
# Sega Master System
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The Sega Master System was a popular gaming console running on z80. It has a
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simple, solid design and, most interestingly of all, its even more popular
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successor, the Megadrive (Genesis) had a z80 system for compatibility!
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This makes this platform *very* scavenge-friendly and worth working on.
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[SMS Power][smspower] is an awesome technical resource to develop for this
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platform and this is where most of my information comes from.
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This platform is tight on RAM. It has 8k of it. However, if you have extra RAM,
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you can put it on your cartridge.
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## Related recipes
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This recipe is for installing a minimal Collapse OS system on the SMS. There
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are other recipes related to the SMS:
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* [Interfacing a PS/2 keyboard](kbd/README.md)
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## Gathering parts
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* [zasm][zasm]
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* A Sega Master System or a MegaDrive (Genesis). (I have only tested on a
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MegaDrive so far)
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* A Megadrive D-pad controller.
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* A way to get an arbitrary ROM to run on the SMS. Either through a writable
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ROM card or an [Everdrive][everdrive].
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## Build the ROM
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Running `make` will produce a `os.sms` ROM that can be put as is on a SD card
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to the everdrive or flashed as is on a writable ROM cart. Then, just run the
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thing!
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## Usage
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On boot, you will get a regular Collapse OS BASIC shell. See the rest of the
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documentation for shell usage instructions.
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The particularity here is that, unlike with the RC2014, we don't access Collapse
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OS through a serial link. Our input is a D-Pad and our output is a TV. The
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screen is 32x28 characters. A bit tight, but usable.
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D-Pad is used as follow:
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* There's always an active cursor. On boot, it shows "a".
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* Up/Down increase/decrease the value of the cursor.
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* Left/Right does the same, by increments of 5.
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* A button is backspace.
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* B button skips cursor to next "class" (number, lowcase, upcase, symbols).
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* C button "enters" cursor character and advance the cursor by one.
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* Start button is like pressing Return.
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Of course, that's not a fun way to enter text, but using the D-Pad is the
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easiest way to get started which doesn't require soldering. Your next step after
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that would be to [build a PS/2 keyboard adapter!](kbd/README.md)
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[smspower]: http://www.smspower.org
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[everdrive]: https://krikzz.com
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[zasm]: ../../tools/emul
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